slow pin i/o manipulation

I'm starting with the Coldfire V2, I just buy a training card with MCF52223.I was training with the most common device: I2C, UART ... However, I have a problem with the fast change state of a pin, I explain:My Quartz is 48 Mhz, the Pll seems set correctly (I have a frequency of 80 MHz output CLKOUT), but the maximum frequency change of state is only 3.63 Mhz, is this normal or due to limitation ?I watched the assembler code and it seems the simplest:

That seems about right for programmatic GPIO pin control. Depending on what you are trying to do, a DMA Timer might get you faster pin transitions, with more precise control.

From the manual:

When a timer reaches the reference value selected by DTRR, it can send an output signal on DTOUTn. DTOUTn can be an active-low pulse or a toggle of the current output, as selected by the DTMRn[OM] bit.